On Thursday, 11 February 2021 6:55:10 PM AEDT Christoph Hellwig wrote: > On Wed, Feb 10, 2021 at 01:59:13PM -0400, Jason Gunthorpe wrote: > > Really what you want to do here is leave the CPU page in the VMA and > > the page tables where it started and deny CPU access to the page. Then > > all the proper machinery will continue to work. > > > > IMHO "migration" is the wrong idea if the data isn't actually moving. > > Agreed. I chose "migration" because device private pages seemed like a good way of reusing existing code to do what was required (a callback on CPU access). However I have been reworking this to use mmu notifiers as the callback and it seems to simplify some things nicely so think I also agree. It removes the requirement for the pin as well which is nice, I'll post it as a v2 soon. - Alistair
